The present invention discloses a process for extraction of oil from the  Valerianajatamansi Jones by Supercritical Fluid extraction (SFE) process with and without co-solvent. The extraction method is performed on the comminuted Valeriana jatamansi Jones using different mesh size of root / rhizome under a pressure ranging from about 220-360 bar and temperature about 45 ⁰C utilizing carbon dioxide as a supercritical fluid. Further the volatile fractions are separated from the supercritical fluid at reduced pressure in the range of about 10-60 bar. Later the same material has been extracted with polar solvent (ethanol) as the co-solvent. The qualitative comparison of essential oil has been done between the essential oil obtained from Hydro distillation and Supercritical Fluid Extraction.